Graduation Project presentation

Intelligent Line Balancing Conceptualization of Model Development of software moduleBy, Harish Manmohan Mithrahari Kumar

PRESENTATION OUTLINE Problems with traditional balancing technique Explanation of the Model through a case Demo of the software solution

OBJECTIVE :To develop a Real-time software solution supported by a self developed mathematical model which identifies bottlenecks and balances the assembly line by autoassigning excess work to multi-skilled workers having idle time with due regard to practical constraints.

AIM: Eliminating the dependency on supervisors by applying computer based modules for Line Balancing where human brain is prone to errors and computers can yield faster and accurate reactions.

LINE BALANCING: The task of allocating / reallocating workers to workstations/operations so as to prevent bottlenecks from occurring with an ultimate aim to meet targets set and thus to maximize the utilization of workers and workstations is called line balancing.

BALANCING INVOLVES It involves basic but accurate, instant arithmetic calculation keeping in mind the following factors Skills available Performance levels Machines & attachments Absenteeism levels Daily/hourly output required Sequence of operations Work content of each operation

Why assembly line with ETON ? Availability of live data regarding Output from operators WIP levels at individual workstations Instant breakdown notifications Dynamic rerouting facility of work Scope of maintaining variable WIP

PROBLEM: The traditional line balancing designates the supervisor being in charge for decision making regarding line balancing Minimum qualified in most cases. More of rectifying approach rather than corrective. Experience ? Accuracy and speed of decisions being made ? When absent , then ?

CASE DESCRIPTION Process is the assembly of formal shirt Assembly SAM 11.03 secs = 662 secs Utilization & efficiency of 90 percent Absenteeism of 9 percent. There are 17 operators and 2 floaters available altogether. A shift of 8 hours. Opening or initial WIP of 20 pieces are available at every workstation at the beginning. An expected delay of 60 mins is determined altogether. A maximum WIP of 40 pieces is allowed at the max. On the second day, operators 4 and 16 are absent.

OPERATION BREAKDOWN

CAPACITY ANALYSIS The total man mins available per hour is (Number of operators available * mins per hour) = 19 * 60 =1140 man mins Ideal capacity per hour is (Total man mins available / SMV of assembly) (1140 * 60) / 662 = 103 garments per hour

Equalizing it to absentisem, utilization and efficiency gives 103 * ((100-9)/100) *((90)/100)*((90)/100)= 80 pieces per hour

INITIAL BALANCEIdeal allocation of operators to operations and their respective workstations before production begins

Is PURELY theoretical as it assumes the most ideal conditions The conditions that are assumed during initial balance are: 100 percent attendance. Operators perform exactly to their potentials 100 percent utilization of resources (machinery and workforce). No machine breakdowns or such unforeseen discrepancies. No requirements of floaters. No quality problems being faced.

USUAL APPROACHES INTRINSIC: This approach aims at just meeting the targets set. Looks out for the closest match. DYNAMIC: Objective of this approach is to achieve the best possible outputs. Concentrates on allocating operations to operators who are of the highest performances. IGNORES Flexibility of the operator Best possible output Optimum utilization

SOLUTIONS FORMULATED The model stresses on "PRIORITIZING operations and operators for allocation" Two techniques of prioritizing have been addressed Manning w.r.t SLOWEST OPERATION "the slowest operation dictates the lines output" Manning w.r.t OPEATOR SKILL INDEX "least skilled operator is a constraint for better utilization"

INITIAL BALANCING PROCEDUREArrange the operations in the descending order of their work contents

Operators available for the slowest operation are short listed.

OPERATORS SKILL INDEX ARE NOTED

The operator with minimum skill index (operator 6) is given first preference of consideration That operator s (operator 6) capabilities of other operations are compared with the currently considering operation That is operator 6 can do 32 pieces in an hour at operation 5 She can do (operator 6) 57 pieces in an hour at operation 7 This clearly states that operator 6 is suitable for operation 7 Possibilities of operator clubbing is also considered since workforce to operation ratio is 17:13 Comparison of output with targets is done. Allocation is thus attained and the outcome is as follows

ALLOCATION IS THUS ATTAINED AND THE OUTCOME IS AS FOLLOWS

FLOW CHART FOR INITIAL BALANCE

BALANCE CONTROL This difference in performance between expected and potential is then converted into differences in pieces produced every hour

ABSENTEEISM As per the case, operators 4 and 16 are absent Therefore fresh day-day capacity analysis (Remaining man mins / SMV) * efficiency*utilization (1020/11.03)*0.9*0.9 = 72 pieces per hour is the revised target

RE-BALANCE INCLUDING FLOATERS

RE-BALANCE WITHOUT FLOATERS

WIP ANALYSIS. Work in process plays a crucial role in keeping an operator engaged incase of any discrepancies Case = 60 mins of delay Minimum WIP = (total delay in line/no of operators in line) average SMV of line = (60/17)/0.95 = 5 pieces approx (minimum)

BEYOND BALANCING - SIMULATION

CASE: The operation 4 is faster than its predecessor and thats why it replenishes work faster and ends up with no WIP in the end. The opening WIP between operations 4 and 3 is 20 pieces, since operation 4 is faster than operation 3 by 49 pieces it takes. (20 / 49) * 60 = 24 mins approximately to reach zero The duration to reach 5 pieces of WIP would be the time taken to replenish 15 pieces.. = (15/49)*60 = 18 mins

BEYOND BOTTLENECK

RE-ALLOCATION . Henceforth this operator who has been depleting her WIP and thus ending with no work can be shifted to the operation which is in need of extra man minutes (operations 7 & 10 in this case)

As operator 15, olive is capable of doing operation 10 at the rate of 30 pieces per hour. She can be shifted to the operation 10

It is of immense importance to determine till what time should the shifted operator work on the operation.

LOGIC The model developed formulates two such criteria to determine the duration of shift between operators According to this the worker works on the job Until her own actual operations WIP level rises over the maximum limit 50-5 = till WIP level reaches 45, predecessors out is 63 pcs per hour time taken to produce 45 pcs by predecessor is 60/63 * 45 = 42 mins Or until the present operations WIP level is about to fall below the minimum level Case: Olive helps giri, = output raises to 66 pcs Predecessors output is 88 pcs == cannot catch up.

SHUFFLING PATTERNS After 18 mins Joseph to madhu extra 33 pieces/hr in rest 42 mins After 23 mins olive to giri extra 36 pieces/hr in rest 33 mins After 20 mins qutub to giri extra 20 pieces/hr in rest 40 mins After 45 mins anil to edwin extra 13 pieces/hr in rest 42 mins

COMPARISION: PROJECTED VS SHUFFLED

Suggestions Current Grading procedure :skill and performance depth but not mere skill width

WIP determination procedure:equal optimum WIP throughout the line is not favorable

Extra emphasize on the slowest operation:the chain is as strong as the weakest link

Day/day target to be entertained:potential capacity levels change w.r.t absenteeism too